You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
52 lines
1.9 KiB
52 lines
1.9 KiB
import numpy as np
|
|
import torch
|
|
|
|
|
|
def one_hot(x, num_classes, on_value=1., off_value=0., device='cuda'):
|
|
x = x.long().view(-1, 1)
|
|
return torch.full((x.size()[0], num_classes), off_value, device=device).scatter_(1, x, on_value)
|
|
|
|
|
|
def mixup_target(target, num_classes, lam=1., smoothing=0.0, device='cuda'):
|
|
off_value = smoothing / num_classes
|
|
on_value = 1. - smoothing + off_value
|
|
y1 = one_hot(target, num_classes, on_value=on_value, off_value=off_value, device=device)
|
|
y2 = one_hot(target.flip(0), num_classes, on_value=on_value, off_value=off_value, device=device)
|
|
return lam*y1 + (1. - lam)*y2
|
|
|
|
|
|
def mixup_batch(input, target, alpha=0.2, num_classes=1000, smoothing=0.1, disable=False):
|
|
lam = 1.
|
|
if not disable:
|
|
lam = np.random.beta(alpha, alpha)
|
|
input = input.mul(lam).add_(1 - lam, input.flip(0))
|
|
target = mixup_target(target, num_classes, lam, smoothing)
|
|
return input, target
|
|
|
|
|
|
class FastCollateMixup:
|
|
|
|
def __init__(self, mixup_alpha=1., label_smoothing=0.1, num_classes=1000):
|
|
self.mixup_alpha = mixup_alpha
|
|
self.label_smoothing = label_smoothing
|
|
self.num_classes = num_classes
|
|
self.mixup_enabled = True
|
|
|
|
def __call__(self, batch):
|
|
batch_size = len(batch)
|
|
lam = 1.
|
|
if self.mixup_enabled:
|
|
lam = np.random.beta(self.mixup_alpha, self.mixup_alpha)
|
|
|
|
target = torch.tensor([b[1] for b in batch], dtype=torch.int64)
|
|
target = mixup_target(target, self.num_classes, lam, self.label_smoothing, device='cpu')
|
|
|
|
tensor = torch.zeros((batch_size, *batch[0][0].shape), dtype=torch.uint8)
|
|
for i in range(batch_size):
|
|
mixed = batch[i][0].astype(np.float32) * lam + \
|
|
batch[batch_size - i - 1][0].astype(np.float32) * (1 - lam)
|
|
np.round(mixed, out=mixed)
|
|
tensor[i] += torch.from_numpy(mixed.astype(np.uint8))
|
|
|
|
return tensor, target
|